Hospitals across the country cancelled non-urgent surgery as they coped with staff absences and increased emergency admissions brought on by heavy snow.
London and the South were particularly badly affected yesterday, with many operating urgent services only.
There were high rates of absence and NHS London urged staff who could not reach their workplace to offer help at other nearby hospitals.
Among trusts confirming non-urgent services were significantly affected were Barts and the London and Guy's and St Thomas'. Most trusts in Greater London are thought to have restricted outpatient work.
Several ambulance services prioritised life-threatening calls and issued advice asking others to use alternatives.
London Ambulance Service trust said it received about 50 per cent more calls than usual.
West Midlands Ambulance Service said there were 10 per cent more calls overall and 26 per cent were fall-related - compared with a usual 10 per cent.
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